The present invention relates to cassette loading mechanisms for use in magnetic recording-playback devices such as VTRs for removably loading a cassette onto the chassis of the device.
FIG. 9 is a perspective view of a cassette 6 and a tray 3 for holding the cassette 6 as will be described below. The tray 3 has wall plates 32, 32 provided upright at opposite sides thereof and each having two pins 30, 31 projecting outward therefrom. The tray 3 has a lug 33 projecting upward from its front end and to be pushed by the front end of the cassette 6.
The present applicant has previously disclosed a cassette loading mechanism shown in FIG. 10 ( see U.S. Pat. No. 5,535,071). The tray 3 described is provided inwardly of side plates 2 disposed upright on a chassis 1 and has its pins 30, 31 fitted in respective first and second guide slits 20, 21 formed in the side plate 2.
Three gears 5, 50, 51 are arranged on the outer side of the side plate 2. The gear 51 in the most downstream position is provided with a leg 52 having the pin 31 of the tray 3 fitted therein. When the gear 5 in the most upstream position is rotatingly driven, the gear 51 rotates, moving the tray 3 along the guide slots 20, 21.
Projecting from a side wall of the chassis 1 are a pair of support members 9, 9. A loading member 4 extending in the cassette loading direction for driving the tray 3 has the support members 9, 9 fitted therein. The loading member 4 is formed with mount openings 92, 92 for the two corresponding support members 9, 9 to fit in and with a rack 40 at its upper end. Each support member 9 comprises a shank 90 and a head 91 of increased diameter at the outer end of the shank. The mount opening 92 comprises a slit 93 extending in the cassette loading direction and a large hole 94 formed at one end of the slit 93 for the head 91 to fit in.
In mounting the loading member 4 on the chassis 1, the head 91 of each support member 9 is positioned as opposed to the large hole 94 of the corresponding mount opening 92, and the loading member 4 is fitted around the support member 9. Next, the loading member 4 is moved toward a cassette ejecting direction a distance a (see FIG. 10) to cause the shank 90 to fit into the slit 93. The loading member 4 is prevented from slipping off the chassis 1 by the head 91 of the support member 9. The side plate 2 provided with the gear 5, etc. is thereafter attached to the chassis 1. The gear 5 is in mesh with the rack 40 when the mechanism is in condition for the start of cassette loading.
Provided on the rear side of the chassis 1 is an operation gear 10 rotatable by a motor (not shown) and meshing with teeth 53 projecting from the lower end of the loading member 4. The rotation of the operation gear 10 is transmitted to the gear 5 by the loading member 4.
FIGS. 11A and 11B are right side elevations of the cassette loading mechanism, FIG. 11A showing the mechanism in a standby state for cassette loading, FIG. 11B showing the mechanism during cassette loading. When the cassette 6 is placed onto the tray 3 in the standby state, a cassette-in sensor switch (not shown) disposed on the path of travel of the tray 3 is turned on, whereupon the operation gear 10 (see FIG. 10) is rotated. This moves the loading member 4 and the tray 3, loading the cassette 6 in place.
However, the conventional cassette loading mechanism has the following problems.
When used singly, the support member 9 is unable to support the loading member 4 with good stability, so that the loading member 4 needs to be supported by at least two support members 9, 9 which are arranged at different locations.
Since the mount openings 92, 92 of the loading member 4 are arranged side by side along the cassette loading direction as seen in FIG. 10, the loading member 4 becomes elongated and large-sized. The chassis 1 provided with the support members 9, 9 is also large-sized.
Further the loading member 4 is fitted around each support member 9 and then moved toward the cassette ejecting direction a distance a for mounting. If this distance a is short, however, the loading member 4 is likely to slip off the chassis 1 when the chassis 1 is subjected to an impact while attaching the side plate 2 to the chassis 1. The distance a therefore needs to be great. This also makes the loading member 4 and the chassis 1 large-sized. Whereas it is required that such a magnetic recording-playback device be compact in its entirety, the loading member 4 and the chassis 1 which are large-sized are in conflict with this requirement.
An object of the present invention is to compact the member for driving the tray and the chassis.
A side plate 2 disposed upright on a chassis 1 is provided with engaging pieces 8, 80 parallel to each other and corresponding to an upper end and a lower end of a loading member 4.
The loading member 4 is formed, in the end thereof corresponding to one of the engaging pieces 8, 80, with a cutout 49 for permitting the loading member 4 to move to inside the engaging piece 80 when positioned for mounting on the side plate 2.
The loading member 4 is mounted on the side plate 2 by fitting the end thereof not having the cutout 49 to the other engaging piece 8 of the side plate 2 and causing the other end of the loading member 4 to clear the engaging piece 80 at the cutout 49 and to move to inside of the engaging piece 80. The loading member 4 is slidable from the mounted position to move within a range in which the loading member 4 is in engagement with the side plate 2.
The engaging pieces 8, 80 are provided on the side late 2 in corresponding relation with the upper end and the lower end of the loading member 4 and therefore serve to make the loading member more compact than in the conventional mechanism wherein the two mount openings in the loading member are arranged side by side along the loading direction.
When the loading member 4 is positioned for mounting on the side plate 2, the upper end or lower end of the loading member 4 is in engagement with the engaging piece 8. Accordingly, the loading member 4 can be engaged with the side plate 2 by sliding the member 4 from the mounting position such a distance that the upper or lower end of the loading member 4 which is out of engagement in the mounting position is engaged by the other engaging piece 80.
When in the mounting position, the conventional loading member 4 is not engaged with the chassis 1 and is therefore likely to slip off the support members 9, 9 unless the distance a the member 4 is to be moved from the mounting position is great (see FIG. 10). According to the present invention, however, the loading member 4, when positioned for mounting, has its upper or lower end already engaged with the side plate 2 and is less likely to slip off inadvertently from this position. This shortens the distance a the loading member 4 is to be slidingly moved from the mounting position for engagement with the side plate 2, consequently compacting the loading member 4 and the chassis 1 having the side plate 2.